On Tue, 2019-10-29 at 16:33 -0700, Kees Cook wrote: > On Thu, Oct 03, 2019 at 02:23:56PM -0700, Rick Edgecombe wrote: > > Add a new CPUID leaf to hold the contents of CPUID 0x40000030 EAX to > > detect KVM defined generic VMM features. > > > > The leaf was proposed to allow KVM to communicate features that are > > defined by KVM, but available for any VMM to implement. > > > > Add cpu_feature_enabled() support for features in this leaf (KVM XO), and > > a pgtable_kvmxo_enabled() helper similar to pgtable_l5_enabled() so that > > pgtable_kvmxo_enabled() can be used in early code that includes > > arch/x86/include/asm/sparsemem.h. > > > > Lastly, in head64.c detect and this feature and perform necessary > > adjustments to physical_mask. > > Can this be exposed to /proc/cpuinfo so a guest userspace can determine > if this feature is enabled? > > -Kees Is there a good place to expose the information that the PROT_EXEC and !PROT_READ combo creates execute-only memory? This way apps can check one place for the support and not worry about the implementation whether it's this, x86 pkeys, arm or other.
